TL431 LINEAR INTEGRATED CIRCUIT
1
PROGRAMMABLE PRECISION
REFERENCE
DESCRIPTION
The Contek TL431 is a three-terminal adjustable regulator
with a guaranteed thermal stability over applicable
temperature ranges. The output voltage may be set to any
value between Vref(approximately 2.5V) and 36 V with two
external resistors. It provides very wide applications, including
shunt regulator, series regulator, switching regulator, voltage
reference and others.
FEATURES
*Programmable output Voltage to 36V.
*Low dynamic output impedance 0.2W
*Sink current capability of 1.0 to 100mA.
*Equivalent full-range temperature coefficient of 50ppm/ C
typical for operation over full rated operating temperature
range.
TO-92
1
SOP-8
SOT-89
1
SOP-8 1: Cathode 2,3,6,7: Anode 8:Ref.
4,5: N.C.
TO-92 1: Ref; 2:Anode; 3:Cathode
SOT-89 1: Ref; 2:Anode; 3:Cathode
BLOCK DIAGRAM
2.5V Vref
CATHODE
ANODE
REFERENCE CATHODE
(K)
ANODE(A)
REFERENCE
(R)
Contek
CONTEK
Contek Microelectronics Co.,Ltd.
http://www.contek-ic.com E-mail:sales@contek-ic.com
TL431 LINEAR INTEGRATED CIRCUIT
2
ABSOLUTE MAXIMUM RATINGS (Operating temperature range applies unless otherwise specified))
PARAMETER SYMBOL VALUE UNIT
Cathode Voltage VKA 37 V
Cathode Current Range(Continuous) IKA -100 ~ +150 mA
Reference Input Current Range Iref 0.05 ~ +10 mA
Power Dissipation
TO-92
SOP-8
SOT-89
PD500
300
350
mW
mW
Operating Junction Temperature Topr -20 ~ +85 C
Storage Temperature Temperature Tstg -65 ~ +150 C
RECOMMENDED OPERATING CONDITIONS
PARAMETER SYMBOL MIN TYP MAX UNIT
Cathode Voltage VKA VREF 36 V
Cathode Current IKA 10 mA
ELECTRICAL CHARACTERISTICS(Ta=25 C, unless otherwise specified)
PARAMETER SYMBOL TEST CONDITIONS MIN TYP MAX UNIT
Reference Input Voltage Vref VKA=VREF,IKA=10mA 2.440 2.495 2.550 V
Deviation of reference Input Voltage
Over temperature(note 1)
DVref/DTVKA=VREF,IKA=10mA
TMIN<=TA<=TMAX
4.5 17 mV
Ratio of Change in Reference Input
Voltage to the Change in Cathode
Voltage
DVref /DVKA IKA=10mA
VKA=10V~VREF
VKA=36V~10V
-1.0 -2.7
-2.0
mV/V
-0.5
Reference Input Current Iref IKA=10mA,R1=10kW,R2= 1.5 4 mA
Deviation of Reference Input Current
Over Full Temperature Range
DIref/DTIKA=10mA,R1=10kW,R2=
TA=full Temperature
0.4 1.2 mA
Minimum Cathode Current for
Regulation
IKA(min) VKA=VREF 0.45 1.0 mA
Off-State Cathode Current IKA(OFF) VKA=36V,VREF=0 0.05 1.0 mA
Dynamic Impedance ZKA VKA=VREF,IKA=1 to 100mA
f1.0kHz
0.15 0.5 W
Note:TMIN=0 C,TMAX=+70 C
Remark: Reference voltage of =-1% tolerance is also available per customer s request.
CONTEK
Contek Microelectronics Co.,Ltd.
http://www.contek-ic.com E-mail:sales@contek-ic.com
TL431 LINEAR INTEGRATED CIRCUIT
3
TYPICAL PERFORMANCE CHARACTERISTICS
-2 -1 0 1 2 3
-100
-75
-50
-25
0
25
50
75
100
125
Cathode Voltage (V)
Cathode Current (mA)
Fig 1 Cathode Current Vs Cathode Voltage
Ta=25 C
VKA =V REF
-1 1023
-200
0
400
200
600
800
-2
Cathode Voltage (V)
Cathode Current (mA)
Fig 2 Cathode Current Vs Cathode Voltage
Ta=25 C
VKA =V REF
IKA(min)
0 5 10 15 20 25 30 35 40
0
-5
-10
-15
-20
-25
-30
-35
-40
Cathode Voltage (V)
Change In Reference INput
Voltage (mV)
Fig 3 Change in Reference Input Voltage
Vs Cathode voltage
IKA =100mA
Ta=25 C
0 1234567
0
1
2
3
4
5
6
7
Time ( m s)
Input and Output Voltage (V)
Fig 4 Pulse Response
Ta=25 C
2
10
1
10
-1
10
0
10
7
10
6
10
5
1010 4
10 3
Impedance ( )
Frequency (Hz)
Fig 5 Dynamic Impedance
Vs Frequency
Ta=25 C
IKA =0mA to 100mA
-10
0
10
20
30
40
50
60
70
7
10
6
10
5
1010 4
10 3
Fig 6 Small Signal Voltage Amplification Vs Frequency
Voltage Amplification (dB)
Frequency (Hz)
Ta=25 C
IKA =10mA
CONTEK
Contek Microelectronics Co.,Ltd.
http://www.contek-ic.com E-mail:sales@contek-ic.com
TL431 LINEAR INTEGRATED CIRCUIT
4
TEST CIRCUIT
INPUT VKA
VREF
IKA
Contek TL431
R1
R2
IREF
VKA=VREF*( 1+R1/R2)+IREF*R1
INPUT VKA
VREF
IKA
ContekTL431
INPUT VKA
IKA(OFF)
Contek TL431
Fig 7 Test Circuit For VKA=VREF Fig 8 Test Circuit for VKA >= VREF Fig 9 Test Circuit For IKA(OFF)
APPLICATION CIRCUIT
Vi Vo
VREF
Contek
TL431
R1
R2
Vo=(1+R1/R2)*VREF
Vi Vo
VREF
Contek
TL431
R1
R2
Vo=(1+R1/R2)*VREF
Contek7805 OUT
IN
COMMON
Vi Vo
VREF
Contek
TL431
R1
R2
Vo=(1+R1/R2)*VREF
Fig 10 Shutdown Regulator Fig 11 Output Control of a Three Fig 12 Higher-current Shunt Regulator
-Terminal Fixed Regulator
Vi Vo
Contek TL431
Rs
RS=VREF/RCL
RCL
Io
Vi
Vo
Contek TL431
Rs
Io
IO=VREF/RS
Fig 13 Constant-current Sink Fig 14 Current Limiting or Current Source
CONTEK
Contek Microelectronics Co.,Ltd.
http://www.contek-ic.com E-mail:sales@contek-ic.com
